Peeking on Sister
by lelouch0zerogeass
Summary: After Kiriko Endo had left Fakubei Hattori, the father of Kanna Endo, she knew she would eventually have to leave Kanna in the care of her family to create a vaccine against Friend's virus. What happens though when she discovers that her younger brother, Kenji Endo, is attracted towards her. This fanfiction is rated M for mature content. Viewer discretion is advised.
1. Chapter 1

Kiriko Endo sat in the rocking chair in one corner of the bedroom she had resided in for more than ten years of her life, breastfeeding her newborn daughter. She was unmarried; she had left Fakubei Hattori, the young man who was the father of Kanna Endo, when she learnt about Friend's creed, and now Kiriko had the job of bringing her daughter up by herself. Still, it was not all that despairing since his mother, Jiyo Endo, and younger brother, Kenji Endo, were there to assist her in any way they could, which is why she was here at home.

She knew she would eventually have to leave her daughter behind with her family to pursue the creation of a vaccine against the virus Friend was going to use as a weapon, but there were still so many things she wanted to do. Having the baby of the man who seduced and deceived her initially felt like a slight misfortune. But even while watching her little girl feed on her mother's breasts, Kiriko knew in her heart that her baby girl was not an error or a misfortune. Kanna was definitely no inconvenience.

When she pondered about it, which Kiriko had done many times, she had to confess that getting impregnated was just as much her responsibility as it had been Fakubei's fault. First, had she not fallen for a stranger's charisma so easily, she would have not been so easily manipulated. Had she used her head a little and thought a step ahead, she would never have gotten seduced. But that was the dilemma: had she rejected his advances, she and Fakubei would not have slept together and she would not have Kanna in her life now. Damned if you do and damned if you don't.

Secondly - and this went a way back toward the reason she did not insist on Fakubei using protection - Kiriko had unusually strong sexual desires. She was hooked to intercourse. Since the night she lost her virginity to her late boyfriend, Moroboshi, the young woman had been almost engulfed by sexual desires that were many times extremely strong.

Kiriko's daughter finally had enough and the young mother swayed the small girl to slumber. As she placed Kanna in her cradle, Kiriko caught a tiny noise at the bedroom door. She smirked as she moved away from the cradle and took a seat on the edge of her bed. She knew the origin of the sound: her younger brother had made a routine of spying her breastfeed his niece, hoping to steal a glimpse of her milk-filled breasts. It had not taken a rocket scientist to know the reason for Kenji's visit outside her door every time she fed Kanna.

It was because her younger brother was a young adult and loaded with the usual sexual compulsions of a male his age that Kiriko had not protested against Kenji taking a peek at her tits when she fed her baby. After all, she had the same problem; there had been countless nights, especially while she was pregnant and wanting a manhood in her soaking moist womanhood, that she had felt the same mind-gnawing desires. And that was why Kiriko had begun opening her top wide when she breastfed Kanna, so that both of her tits were revealed to Kenji.

Kiriko was not sexually engrossed in her little brother, even though he was viewed as a stud by females his age, and it did not mean that she was unconcerned about his difficulty. She was aware that guys Kenji's age liked to take the rare peep at a mother or sister's naked figure – it was just the way of young males, and as much a bit of the developing experience as consuming sufficient calcium for their bones. Kiriko also did not find it fair that (she could not really explain why she thought this) her younger brother should skulk around. Perhaps because of her own sexual tendencies, or the absence of reservations, that she did not mind allowing her younger brother look at her tits.

Kenji was still standing in the corridor, looking closely through the door, which was open about eight, perhaps ten inches. Kiriko knew that as long as her tits were uncovered, her younger brother would remain in the corridor peering through the door. In a way, she felt complimented by his interest towards her. She sweeped a lengthy thread of hair from her face and shrugged from the loose upper garment. It was the first time she had completely revealed her tits this way in front of Kenji and she thought she heard an lengthy moan approaching from the corridor.

"Kenji, come here, please," she called out all of a sudden. She listened and waited, then after a few minutes, she said, "I know you're out there, Kenji."

The door swung open gradually and she revolved her head to watch her little brother slide into her bedroom. She smirked when she saw how hard he attempted to stop his eyes from going to her milk-filled tits. As he proceeded more into the room she pretended not to notice the swelling in his boxers that he was casually attempting to conceal with one hand.

"Sit down, baby brother," she said pointing at the desk chair a couple of feet from where she sat on the border of the bed. "I want to speak with you."

"Um, do you think you might want to cover up?" he chuckled. His voice unintentionally revealed his anxiety.

"Why? You were out in the corridor for half-an-hour watching me feed Emily." Kirko smirked when she noticed Kenji's face turn a shining scarlet. "You've been catching glances at my breasts for a minimum of 2 weeks."

"I-I'm s-so s-sorry," he stuttered. "I won't do it again. I promise."

Kiriko smiled. "Don't fret, Kenji, I'm not angry but you should be cautious or mom could catch you."

"I know, and I am."

Kenji seemed glad that he was not in trouble. Still, even when she slanted back on the bed a bit, shoving her tits out, his eyes still flickered and searched for other things to glance at. In a way she could perceive the reason for her younger brother's obsession with staring at her breasts and she just did not find anything illegal with it as most females her age would.

"I don't mind if you stare at my breasts, Kenji," she smiled. "I mean it won't lead to anything unpleasant and it's not like we're rolling in bed. Besides, it's complimentary that my younger brother enjoys staring at my breasts."

"Really?"

"Really," she beamed radiantly.

Initially he was not comfortable staring at his older sister so boldly but eventually Kenji breathed in deeply and let his eyes fall to his older sister's tits. They were not large, even with milk in them, but they had an appealing form with good fat nipples that she knew made guys mad. And Kiriko noticed the familiar air of hunger in her younger brother's eyes as he ogled at them.

"Why do you like staring at my breasts?" she inquired after a couple of minutes of observing Kenji leering at the milk-filled spheres. "You're very handsome and you must know many women who have larger and prettier breasts than mine."

"I...well, I think you're hot and sexy," he spoke in a low, hesitating voice.

"Really?" Kiriko was astonished. Her younger brother's unexpected disclosure was a bit startling. "I'm your older sister, Kenji. Doesn't that bother you?"

He paused for a second, clearly feeling awkward. "Yeah, I'm aware you're my older sister and you most definitely think I'm a perv, now."

"No, I don't," she smiled. Then she raised her shoulders slightly and momentarily, expressing indifference. "You're not the sole man who...I don't know...has ever had an infatuation for his older sister. Do you have an infatuation for me?"

Kenji dropped his chin for a second, and then exhaled. "Kind of, I suppose."

Kiriko gazed at Kenji for a little while. He was clearly uncomfortable and uneasy after divulging his sentiments. In a way, knowing that Kenji was interested in her was even more appealing than she could have imagined. And she disliked seeing him so ill at ease.

"Hey. Have you ever tasted a female's milk?" she questioned cheerfully.

Kenji shook his head as he gazed at his older sister.

She raised her shoulders slightly and momentarily, expressing indifference. She then smiled broadly. "I still have a lot remaining if you would want a taste."

"I-I d-don't k-know..." he stuttered.

"C'mon, younger brother," Kiriko persuaded.

"Does it, you know, taste unpleasant?"

"I've tasted it and I in my opinion it's alright."

"Sure alright," Kenji beamed.

Kiriko had her younger brother sit on the bed to her right facing the wall behind her, then tugged his face to her right breast. When Kenji accepted the nipple into his mouth, the older girl puffed softly. Apart from her daughter, and Kanna did not count, it had been some time since she had felt lips envelop one of her nipples. It felt excellent. She tipped her head back for a second and shut her eyes as Kenji drank milk from her.

Kiriko's breathing turned nonuniform, her heartbeat sped and her temples pulsated with the unforeseen marvelous warmth her younger brother's mouth brought about. As he sucked her right nipple, her younger brother cupped both smooth silky spheres in his hands. She clasped his head with one hand and laid the other on his side. The young female perceived the indications straightaway; she was becoming stirred up by Kenji's treatment to her tits. A short notion that she had to place an end to what they were doing before it all went out of hand crossed her mind but she made no attempts to halt her younger brother from feeding on her tits.

Kiriko could not. It simply was too nice; anyways, it was not as if they were sleeping together. All Kenji was doing was drinking milk from her tits, tasting it, and there was no harm in that. Was there? It had been ages since a guy had taken her nipples into his mouth and there was no harm in having a bit of enjoyment. And the way Kenji's hands worked her mushy tits, the way his lips and mouth squeezed her nipples as he swallowed her milk, simply felt way too marvelous to break off.

"Oh..." she whined softly.

Kiriko had not intended to create any noise, had not even foreseen she was going to until it left her mouth. She stared at Kenji's face but he revealed no indication that he heard her. He looked so blissfully oblivious to everything but her tits and gulping down Kiriko's milk. But she noticed that her younger brother was not sucking her nipples because of the milk in them. Watching the rapture on his face, she straightaway became aware that Kenji was hungrilly eating her nipples, fulfilling a desire he in all likelihood had for years, and she could sense her womanhood become wet with that realization.

Subconsciously, the young female started to press her slim upper legs together, and she could sense her fluids drenching the crotch of her panties beneath the checkered skirt she had on. She was slightly aware that the hand she had laid on Kenji's side just above his boxers was travelling steadily, stroking the compressible, youthful skin of her younger brother's thin waist. She scrutinized her hand in an abstract kind of way as she brushed him, her head a cloud to everything excluding the pleasant way her younger brother made her feel.

Kiriko did not want to feel this way. It was immoral to foster carnal thoughts of her own younger brother, thoughts that any responsible individual would consider to be obscene and unethical. Sexual relations with family members was immoral. She was aware that it had begun decent enough but her emotions were starting to go out of control. Kenji was sucking her nipples and liking it because her figure stirred him up; the young man desire his elder sister in a sexual way that had zero to do with sampling her breast milk. And the way he sucked her nipples, the minute, scarcely hearable sounds of sexual desire that came from his mouth, contradicted the innocence of the activity.

Kiriko's determination was fading, as she had sensed it would. She had never been good at stopping anything carnal once it started. Once the fire of ardor started to blaze in her loins, Kiriko's determination started to vaporize too. Having her nipples sucked for so long and with so much enthusiasm was something the young female liked extremely, and it was having a huge influence on her.

She glanced at the fore of Kenji's boxers and spotted the swelling of his erect penis. The fingertips of her right hand continued to gently stroke his soft stomach as she gazed at the swelling in her younger brother's underwear. She sank her teeth into her lower lip, her brain filled with the battle that stormed within as she wrestled with the desire to hold Kenji's penis. Grasping his firm cock in her palm and caressing it would surely weaken the feeling of moral virtue that her brain had already built, to soften the reality of what was occuring. In truth, Kiriko and Kenji would be engaging in incest.

Kiriko discovered, as she gazed at the enticing swelling, that she did not care. After all, holding his penis, clasping its hardness in her palm and caressing it till he ejaculated, was not all that wrong. It was a bit of mild entertainment that did not actually signify that much. It was not as though she would be receiving her younger brother's penis into her vagina...it was not the same thing. And the more she pondered about it, the more Kiriko persuaded herself that the deed of caressing her younger brother's cock was no more than painless pure enjoyment between an older sister and her younger brother.

Without one more thought, Kiriko drew in a heavy breath and slid her hand through the lengthy gap in Kenji's underpants and swiftly enfolded her long, soft fingers around the wide pole. He gasped softly with a teat in his mouth and Kiriko beamed as she brought his penis into sight. It was attractive, but then she adored all penises. It was not all that long – no doubt about 6 inches, she saw, but it was extremely plump. The huge purple crown shined with pre cum and she softly slid a thumb across the smooth head. Kenji moaned and curved his back, shoving his firm dick nearer to his older sister.

"You like that, younger brother?" she asked softly, her voice thick with ardor. "You like having your older sister fondle your large man-cock?"

"Oh, yes!" he cried out breathlessly.

"It's so large!" she murmured as she tugged on Kenji's penis. "I'm certain you've had sex with many young women with this."

"MMMMM!"

"Suck my tits, younger brother!" Kiriko inhaled suddenly with her mouth open as Kenji softly sunk his teeth into her left teat. "Oh, that feels so nice! Drink my milk!"

Kiriko could not believe that she was speaking like this to her younger brother; trying to persuade him to suck her teats while she jacked his penis off. The magnificent imagery, the marvelous physical perceptions that flowed with great power through her slim figure, the way Kenji suckled her mammary glands and the sensation in her female genitals as she firmly pressed her legs together, was more than she was able to sustain. The beautiful woman realized as she caressed her little brother's penis that she would experience an orgasm soon.

She held her breath for an instant, wanting to hold off till Kenji exploded and blasted his semen. At that instant, the single overwhelming desire that devoured her brain, was watching semen blow up from the attractive crown she was gazing at. She started to pump Kenji harder and quicker, her hand becoming a blur as she jacked him off with firm, speedy strokes. She watched with anxious desire as Kenji started moving his pelvis to and fro and fucking her hand.

"I want you to cum! Cum for me, Kenji! Spray your seed all over me!"

Kenji moaned and she was able to perceive the small tremor from his mouth on her left breast. Kiriko did not have to toil with a great deal of effort for the climax she knew was just around the corner. She only hoped that Kenji would cum quickly so she could surrender and free herself of the strong force that threatened to engulf her.

All of a sudden, Kenji became stiff, then shouted as a viscous, milky cord of his cum blew up from his penis. Kiriko started to shake as she watched each squirt of her younger brother's semen explode from the huge crown and come down on her side, arm and hand. Without even touching herself, the older female fell over the edge into the abyss of her own climax and bit her lips to stop from screaming. Ripple after delicious ripple of the most pleasant climax of her life teared through Kiriko as she clasped her younger brother's penis in her palm.

Eventually, luckily, the volatile climax started to subside and Kiriko released Kenji penis. She panted for breath as she gently moved away from her younger brother. It was then, after the act that the extreme scale of what she and her younger brother had done, grabbed hold and guilt sat in. She had just sexually satisfied her little brother, no matter how she had justified it seconds ago while she tugged on Kenji's penis, and the impact was worrying.

"I-I have to take a bath, Kenji," she uttered, standing from the bed and swiftly pulling her loose upper garment back on.

"Fine. I'll speak to you later," he said. Kenji patted his older sister's arm and departed the room.

* * *

 _To be continued…_

 _If you want me to continue writing this story, please favorite the story, follow it, and LEAVE A REVIEW!_


	2. Chapter 2

It was a little after four in the afternoon when Alex closed his bedroom door and walked to the desk that sat in one corner. He sat in the chair as his mind replayed what had just happened in his older sister's room. The taste of her milk in his mouth, the feel of her nipples as he drank her sweet milk, and the feel of her soft hand on his cock as she jerked him to a mind-numbing orgasm still lingered heavily in his consciousness. It was the most awesome and stimulating event in his life.

Over the years, once he went through puberty, Kenji had developed a powerful lust for his older sister. To him - and every man who could see - Kiriko was a very beautiful woman who exuded more sensuality and sex than most women he had seen in his young life. She had become the object of his desires and, while he had dated and made love to several girls his own age, Kenji was still captivated by his older sister's beauty.

Was it wrong to want Kiriko the way he wanted her? That was the question he had asked himself countless times before. Everyone knew the definition of incest, was aware that it was wrong and he had long ago realized that a sister and brother were not meant to be together in a sexual way. To Kenji, that was the conclusion of society's rather narrow-minded point of view.

When she had asked him if he wanted to taste her breast milk, Kenji's heart had sped up. In order to taste her milk he would have to suckle from her breasts and that was a dream come true. Though it might not be the same as making love to her, joining with Kiriko to become 'one' in the biblical sense that he had lain in bed imaging over the years, it was more than he could ever have hoped for. He had enjoyed the taste of his older sister's breast milk, yet the act of sucking her lovely nipples was what he had wanted.

Hearing her groan as he suckled, hearing Kiriko's harsh, excited breathing, had sent a signal that she enjoyed the feel of his lips on her delicious nipples. The feel of her soft skin as he fondled the milk-heavy globes of her breasts had been intoxicating. When she slipped a hand inside his boxers and wrapped long, soft, slender fingers around the shaft of his hard cock, Kenji had thought nothing else in life would compare to that feeling. To hear his older sister encourage him to cum as she jacked him off, was more than he could have envisioned in his wildest fantasies concerning his lovely sister. And, she had actually had an orgasm while he sucked her nipples and she jacked him off! He had not touched her there, nor had she touched herself. It was incredible!

Then, suddenly, once they both climaxed, Kiriko changed and became somewhat remorseful. He had seen the guilt on her face. He had heard the disgust and shame in her voice and knew that his older sister felt bad for letting herself fall into the pitfall of her own lust. Oh, yes, Kenji was aware that his older sister had long been an addict to the powerful craving of sex. She could not escape the urges that boiled deep within her loins and controlled her with their manipulative impulses that were just too formidable. It was really too bad because for a moment, as she stroked his cock with so much desire, talked to him with a voice filled with lust, he had allowed himself to believe he might actually have a chance to fulfill the strongest fantasy of his life.

Kenji crawled onto his bed, stripped out of his boxers and grasped his cock in one hand. He was hard again as the images of what he had shared with Kiriko flooded his mind. In his mind's eye he saw her breasts, felt her nipples between his lips and recalled the sweet taste of her breast milk on his tongue, and felt the wonderful soft touch of her hand on his cock as she jacked him to orgasm. And it was not long before he came again, sending ropes of hot white cum streaming from his cock to land on his belly and chest. As he lay gasping for breath, the young man wondered if he would ever get the chance to have fun with his older sister again.

* * *

 _To be continued…_

 _Sorry for the long delay. I intend on updating more frequently._

 _If you want me to continue writing this story, please favorite the story, follow it, and LEAVE A REVIEW!_


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